Design Equations for Predicting Stability of Unlined Horseshoe Tunnels in Rock Masses

This paper aims to propose new stability equations for the design of shallow, unlined horseshoe tunnels in rock masses. The computational framework of the upper- and lower-bound finite-element limit analysis is used to numerically derive the stability solutions of this problems using the Hoek–Brown failure criterion. Five dimensionless parameters including the width ratio and the cover-depth ratio of the tunnels, as well as the normalized uniaxial compressive strength, the geological strength index, and the yield parameters of the Hoek–Brown rock masses, are considered in the study. Selected failure mechanisms of the horseshoe tunnels in rock masses are presented to portray the effect of all dimensionless parameters. New design equations for stability analyses of horseshoe tunnels are developed using the technique of nonlinear regression analysis and the average bound solutions. The proposed stability equations are highly accurate and can be used with great confidence by practitioners.

Dieses Werk wurde unter der Creative-Commons-Lizenz Namensnennung 4.0 International (CC-BY 4.0) veröffentlicht und darf unter den Lizenzbedinungen vervielfältigt, verbreitet, öffentlich zugänglich gemacht, sowie abgewandelt und bearbeitet werden. Dabei muss der Urheber bzw. Rechteinhaber genannt und die Lizenzbedingungen eingehalten werden.